Clinicians and behavioral interventionists treating substance using adolescents in medically monitored in- patient residential settings have long emphasized the importance of the social environment outside of this setting as a factor influencing the success or failure of treatment efforts. Yet the in-patient treatment setting is often regarded as discrete, failing to consider the impact of interrelated medical and social contexts including Family and peer relationships. The intertwine of these contexts has not been adequately explored and may have a strong influence on clinical outcomes, as well as adolescent development more generally. The specific aims are 1) To investigate, using ethnographic methods, the transition between in-patient residential substance abuse treatment and community-based out patient treatment; 2) To explore the range of medical and social contexts which may impact clinical improvement overtime; and 3) to examine, using both qualitative and quantitative methods, co-occurring disorders and morbidities. The research focuses on a small cohort [n=12] of index female and male adolescents, their households, healthcare providers, and the treatment environments through which they transition. [unreadable] [unreadable] [unreadable]